You have until the tax deadline of April 17 next year to set up and contribute to most types of IRAs. But some tax-advantaged accounts, including an individual 401(k) or individual Roth 401(k) must be established by Dec. 31. The big one: Roth conversions must be done by year end. Once a savings vehicle for the 99%, the Roth’s income limitations have been lifted and it is now available to everyone. If you convert your traditional IRA to a Roth you’ll get hit with an immediate tax bill. But if your assets are temporarily depressed (whose aren’t?) and you believe tax rates may increase (can you say budget deficit?), converting now may leave you with more later.